/*
 * Copyright 2015-2016 Red Hat, Inc. and/or its affiliates
 * and other contributors as indicated by the @author tags.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.hawkular.apm.agent.opentracing;

import java.util.Iterator;
import java.util.ServiceLoader;

import org.hawkular.apm.api.logging.Logger;

import io.opentracing.Tracer;

/**
 * This class provides helper capabilities to the byteman rules.
 *
 * @author gbrown
 */
public class OpenTracingTracer {

    private static final Logger log = Logger.getLogger(OpenTracingTracer.class.getName());

    private static Tracer tracer;

    public static synchronized Tracer getSingleton() {
        if (tracer == null) {
            // Obtain tracer
            Iterator<Tracer> tracers = ServiceLoader.load(Tracer.class).iterator();
            if (!tracers.hasNext()) {
                log.severe("No tracer available");
            } else {
                tracer = tracers.next();
                if (tracers.hasNext()) {
                    log.severe("Multiple tracers found, selected: " + tracer);
                }
            }
        }
        return tracer;
    }

}
